Pressure-indicator for steam-engines



(No Model.)

F. M. CLARK. PRESSURE INDICATOR POR STBAM ENGINES. No. 430.467. Patented June 17, 1890.

y I -z l B I I pt /6 ia s4 w: u 11 W t d Q's).

n! t {,/""i,

90 fl K .I i) I 12 {I vvitweaoeo Y n6 5 Ba 1' 6 a n S34 6m YNI man. 11:: cm, PnoYo-unqm. wunmaron o c UNITED STATES PATENT OFFICE.

FRANK M. CLARK, OF TILTON, NEW HAMPSHIRE, ASSIGNOR TO THE MECHANI- CAL SPECIALTIES COMPANY, OF BOSTON, MASSACHUSETTS.

FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 430,467, dated June 17, 1890. Application filed November 1, I889. Serial No. 328,888. (No model.)

To all whom it may concern.-

Be it known that I, FRANK M. CLARK, of Tilton, in the county of Belknap, State of New Hampshire, have invented certain new and useful Improvements in Pressure-Indicators for StealaEngines, of which the followin g is a description sufficiently full, clear, and exact to enable any person skilled in the art or science to which said invention appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a sectional elevation of my improved indicator; Fig. 2, a vertical transverse section of the drum, and Fig. 3 a sectional View illustrating details of construction.

Like letters and figures of reference indicate corresponding parts in the different figures of the drawings.

My invention relates to a steai'n-pressure indicator which transcribes an are instead of a straight line on the indicator-card; and it consists in certain novel features hereinafter fully set forth and claimed, the object being to produce a simpler, cheaper, and more effective device of this character than is 110w in ordinary use.

The nature and operation of the improvement will be readily understood by all conversant with such matters from the following explanation.

In the drawings, A represents the body of the indicator; B, the drum or cylinder, and C the card.

The body A consists of a tube threaded at b, in the usual manner, to attach it to the engine. The upper portion of the body is chambered at (Z, and in said chamber a'piston f is fitted to work, its rod g projecting through a screw-cap 71, turned into the upper end thereof. A coiled spring i, disposed around the pistonrod, acts expansively to force said piston downward against the pressure of the steam through the duct j of said body. The body is provided with a two-way cock D. A bracket 70 is secured on the body by means of a checknut m. A sleeve 19 is fitted to rotate on the body between a shoulder q thereon and the cap h, said sleeve being provided at one side with a handle 0' and on the opposite side with an arm 25, which is in position to engage a vertical stop '0 on the bracket It.

. The pencil-lever H'of the indicator is secured at one end to a rod '10, fitted to rotate in the top of a standard 00 on the sleeve-handie 0'. A thumb-nut y is turned onto the outer end of said rod, and a coiled spring ,2, disposed around the rod, has one end secured to said nut and its opposite end to the standard, said spring acting torsionally to depress said lever. The lever has a segmental boss 15, which engages or rests upon the upper end of the piston-rod g. The free end of said lever is provided with a pencil 16. A vertical rod K is secured in the outer end of the bracket 70. A grooved pulley 17, provided with a hub I3,

is fitted to rotate on said rod K. A vertical flange 19 is formed on the pulley, and the card cylinder or drum B is secured thereon. The pulley is provided with a cone-shaped hub 20 on its upper side. A nut or cap 22 is turned onto the upper end of the rod K, said nut being provided on opposite sides with beveled slots 23. A forked spring 24L is disposed astride said nut, its arms projecting downward within the drum and inserted in said slots. A thumbserew 25 passes through the top 26 of the drum and through the flat head 27 of the spring into the top of the rod K. A shoulder 28 is formed on the screw, which engages said spring and forces it downward onto the nut 22 as the screw is turned into the rod K, thereby causing the spring-arms to spread or be forced apart. The lower end of each springarm is provided with a hook, in which a cord 29 is secured, the opposite ends of said cords being secured to the pulley at equal angles to the spring-arms, so that they will wind upon the cone 20 when the drum is rotated. A pin 30 projects downward from the pulley o 17 and engages a stop 31 on the bracket is at each complete rotation thereof. An angular arm 3 is fitted onto the lower end of the rod K, and is secured in position by a thumbnut 33, turned onto said rod. An adjustable 5 sheave-block 34, provided with a pulley 35, is secured by a thumb-nut 36 in the outer end of said arm. A flexible binding strip or clip 37 is secured at one end to the drum, and is adapted to hold the card C in position thereon. 10o

A cord P passes around the horizontal pulley 17 and over the sheave-pulley 35.

In the use of my improvement the body A is turned into the clearance of the engine eylinderin the ordinary manner, and the cord P connected by any suitable reducing ntion with the cross-head thereof. The card 0 being adjusted 011 the drum,the sleeve 1) is turned until its aim tmeets the stop 2, when the pencil 16 engages the card. The steam, acting on the pistonfiforces the pencil-lever upward, giving the height due to pressure, and an arc is produced on the card by the pencil instead of a straight line. The drum being at the same time rotated by the cord P,.

an area is thus produced which is equally accurate with that produced by straight-line motion, and may as readily be measured by the planimeter as when parallel lines are used. As the drum rotates, the cords 29, attached to the pulley 17, are wound upon its cone-hub 20, and, being attached to theforked spring, exert a uniform tension upon the cord I, thus preventing the reducing motion from becomingirregular and distortingthcdiagram on the card. By means of the thumb-nut the tension can readily be adjusted on the gencil-leverand all back lash or play between the pencil and piston g readily overcome. By means of a nut l0 on thelower end of the piston-rod g it may readily be adjusted for changing the position of the at-n'lospheric line on the drum. It will be seen that the tension of the spring .2 upon the pencil-lever holds the lever against the cap it equally on all sides and compensates for all wear thereon, making it practically impossible for the diagram to be distorted from this cause.

By the use of a single pencil-lever tracing an are instead of straight-line motion the area of the diagram is undisturbed, the movement of the pencil-lever being positive and making equal heights for equal pounds of pressure in the cylinder.

The sheave-pulley b5 can be adjusted vertically by detaching it from the arm 32, inverting said arm on the bracket 7., and read justing said sheave therein,as shown by (lotted lines in Fig. 1.

Having thus explained my invention, what I claim isl. A eard-dru m to rasteain-engi ne indicator,

consisting of a rod, a pulley journaled thereon and provided with a cone-shaped hub, a cylinder secured to said pulley, a forked spring astride one end of said rod, and flexible cords connecting the ends of said spring with said pulley, substantially as described.

2. In a steam-engine indicator, the combination of a tubular body, a piston therein, provided with a piston-rod extending through the cap of said body, and a pencil-lever pivoted 011 said body and resting on said piston rod, said lever having a tension-spring at its pivot, substantially as described.

3. In a steam-engine indicator, the combination of a tubular body provided with a spring-cushioned piston provided with a piston-rod extending through the cap of said body, a pivoted spring-tensioned pencil-lever resting on said piston-rod, mechanism' ferrotating said lever on said body, a rotary carddrnm, an actuator therefor, and a forked tension-spring for said drum, substantially as described.

4. In a steam-engine indicator, the combination of a rod K, a pulley 17, rotating thereon and provided with a cone-hub 20, a cylinder l ,mounted on said pulley, a slotted flange or nut 22 on said rod, a forked spring 2.4., dis posed in the slots of said nut, cords 20, connecting said spring with said pulley, and an adjusting-screw 25 for regulating the tension of said spring, substantially as described.

5. In a steam-engine indicator, the combination of a tubular body, a piston therein, provided with a piston-rod, astandard supported on said body, a pencil-lever pivoted to said standard and provided with a tension-spring at the pivot thereof and with a segmental boss which engages said pistonrod, and a rotary drum for carrying the card on which the penoil of the pencil-lever operates, as described.

(I. In a steam-engine indicator, the combination of a tubular body, a piston therein, provided with a piston-rod, and a pivoted springtensioned pencil-lever provided with a segmental boss which engages and slides on said piston-rod, substantially as described.

FRANK M. CLARK.

substantially Witnesses:

K. DURFEE, O. M. Snmv. 

